Th F3A is a dead ringer for the Knuffel -and we have a bunch of those also - in sizes ranging from a smaller one ounce airframe (true) to the 115% 4.9 oz airframes for outdoor whacking about with a 20/20L Hacker. (AUW 12 ozs)
The Knuffel outflies the original shockies - and flies like the F3A Shocky -only more responsive - the horizontal stab is back a bit further .
The Tensor?
well that works great indoors but for outdoor flying - a bit too limber .
It is in my book , totally different in response to the monoplanes like the Shock Flyers and our Knuffels .
The new Shockflyers are really a terrific value - great flyers also.